Alzheimer's disease (AD) is the most common cause of disabling memory and thinking problems in older persons. According to one study, it afflicts about 10% of those over the age of 65 and almost half of those over the age of 85. According to another study, the prevalence of the disorder increases from 1% by the age of 60 years to 40% in nonagenarians. By 2050, the number of afflicted persons is projected to quadruple, leading to approximately 16 million patients and a cost of more than $750 billion per year in the United States alone. In the meantime, the disorder takes a devastating toll on patients and their families. Clinically, AD is characterized by gradual but progressive declines in memory, language skills, the ability to recognize objects or familiar faces, the ability to perform routine tasks, and judgment and reasoning. Associated features commonly include agitation, paranoid delusions, sleepiness, aggressive behaviors, and wandering. In its most severe form, patients may be confused, bed-ridden, unable to control their bladder or bowel functions, or swallow. With the contribution of other problems (e.g., inanition and infections), AD is considered the fourth leading cause of death in the United States.
To date, the FDA has only approved five drugs for the treatment of AD, and all of these treatments only temporarily alleviate symptoms such as cognitive decline and memory loss without affecting changes in neurophysiology. AD pathology includes amyloid plaques and neurofibrillary tangles (NFT), which are made of Aβ(1-42) deposits and hyperphosphorylated tau, respectively. Thus there is a need for therapeutics that decreases amyloid plaque formations, decreases NFT formation, or increases cognitive function.